Embodiments of the subject matter disclosed herein generally relate to systems and apparatuses useable in subsea installations for cooling of heat generating electrical components.
During the past few years, with the increase in price of fossil fuels, the interest in developing new production fields has dramatically increased. However, the availability of land-based production fields is limited. Thus, the industry has now extended drilling to offshore locations, which appear to hold a vast amount of fossil fuel. As oil and gas fields in shallow waters diminish, producers are tapping offshore fields in deeper waters with oil installations that operate far below the surface of the sea. The typical equipment for such subsea oil recovery and production include various above-water and subsea heat generating electrical components, such as gas compressors and various pumps for multiple functions. In many instances, electric variable speed drive (VSD), motor systems, power transformers, uninterruptible power supply, and circuit breaker are examples of such subsea heat generating electrical components.
Typically, alternating current (AC) transmission and distribution systems are used for delivery of power to these subsea heat generating electrical component locations. Such systems typically deliver AC power from a platform or terrestrial location to the subsea heat generating electrical components through a large power cable. The electrical components in the subsea locations generally cannot tolerate high pressures and must be placed in large, thick walled pressure vessels capable of withstanding the high pressures present at various depths of water while maintaining a substantially constant pressure within the pressure vessel. In addition, cooling of these subsea heat generating electrical components is important to secure a reliable production and processing of oil and gas in subsea locations.
In a typical subsea electrical component cooling system, electrical components are immersed in an outer vessel filled with a dielectric oil. This allows for electrical insulation between electrical components and cooling is achieved by the natural convection of the oil. However natural convection cooling of these components is a thermal bottleneck and takes more than 30% of the overall thermal resistance of the system. Accordingly, a cooling concept is desired that allows these heat generating electrical components, to be more effectively cooled, while maintaining electrical isolation from the sea water and its neighboring components.